(CNN) -- The U.S. Coast Guard, with international assistance, continued an expansive search Thursday for 15 people missing after a skiff disappeared about 600 miles southeast of Guam.
"We're now almost 27 hours into the search and so far we've covered over 9,300 square nautical miles of ocean," Coast Guard Ensign Richard Russell said shortly after noon Thursday in Guam (shortly after 10 p.m. Wednesday ET).
Russell said searchers had not found any sign of the boat or the passengers and crew.
The small boat, which carried six children and nine adults, was last seen near Chuuk, a group of islands in the Federated States of Micronesia, on Monday, said the Coast Guard.
It was headed for tiny Ruo Island, also part of the federation, about 70 miles northeast of Chuuk, said the Coast Guard.
Most of the missing people work in Chuuk state and were traveling home to Ruo, according to Petty Officer 3rd Class Anthony Soto of the Coast Guard in Hawaii.
The Chuuk State Department of Transportation reported the boat missing to the Coast Guard Tuesday morning when it was overdue at Ruo Island.
The national government of the Micronesian federation, the Chuuk state government and the Guam sector of the Coast Guard coordinated a joint search to find the boat.
U.S. Navy and Coast Guard aircraft were in the search, the Coast Guard's Russell said, as was a 750-foot Norwegian cargo ship that had been in the area.
"We have a program called AMVER (Automated Mutual Assistance Vessel Rescue) that allows us to track vessels and (in an emergency) we have the ability ask them to change course to search, and that's what they've done," he said.
A Coast Guard cutter based in Guam was also joining the search, Russell said.
He added that although there had been no sign of the boat or the missing people, "We'll search until we've exhausted our capabilities."
The Federated States of Micronesia is a democratic island group in the Pacific Ocean between Hawaii and Indonesia. Independent since 1986, the vast archipelago of hundreds of tiny islands comprises a land mass of just 702 square miles, about the size of Singapore. It includes the Chuuk Islands, Yap Islands, Kosrae and Pohnpei.